Comments on: Polish Inside of Seating Stems to Avoid Ring Marks on Bullets

By: Zach

Zach — Fri, 30 Jul 2021 00:30:54 +0000

VLD stems like those I use from Redding don’t solve this problem? I also thought these rings had no effect on bullet flight.

By: ELR Researcher

ELR Researcher — Tue, 27 Jul 2021 14:05:04 +0000

Then you have David Tubb’s nosering:

http://www.davidtubb.com/index.php?route=product/search&search=nose%20ring

https://www.warner-tool.com/product/338-285gr-flat-line/ – Tubb ring mod option

By: Kevan Daniel

Kevan Daniel — Sun, 21 Mar 2021 03:48:16 +0000

Great. I’ll be trying this. Ran into this issue with 136 grn Lapua Scenar-L’s while loading up a few different bullets to try. It was NOT too much neck tension or a compressed load causing it – and the 3 other bullets were fine. It was also giving grief with consistent seating depth. I had to back off ten thou and turn down each round.

By: Brenden Anderson

Brenden Anderson — Sat, 03 Oct 2020 04:14:04 +0000

This just happens to me with new 6.5 Creedmoor Lapua brass. Great article! Thanks for the tip!

By: Josh Benin

Josh Benin — Thu, 01 Oct 2020 17:17:11 +0000

This is a good idea but horrible execution. Spinning the bullet against a stationary, hand-held seating stem is almost guaranteed to create an eccentric cavity in the stem. Instead, chuck the stem and rotate it against a hand-held bullet.

Editor: Your suggestion is a good one. However, the method shown actually works OK. In practice, it doesn’t take long, the lapping compound provides a bit of a barrier, the stem naturally self-centers.

By: DesertLefty

DesertLefty — Mon, 24 Apr 2017 07:58:18 +0000

What a coincidence! I’ve been working up a mid-range mag-length AR load using the new Sierra 69 gr TMK (I love it!) and I’ve encountered just this problem. I’ve had some deformed bullets that looked even worse than the one in the picture.

In my case, lapping the seater stem to match the bullet’s nose profile helped but didn’t completely solve the problem. (HINT: I ordered some 3.5 micron diamond lapping paste from Amazon for $8 and that worked MUCH better than valve grinding compound from the auto parts store.)

The biggest contributor to my problems turned out to be excessive neck friction, which resulted in very high seating force. Once I solved that issue, the marks from the seater stem essentially went away. So, if you’re getting marks from the seater, make sure that your neck tension (friction), seating force, and bullet removal force are “reasonable”.

I still haven’t got to the root cause of my problem, but it’s probably due to the processing techniques used by my brass supplier. I’m using once-fired Lake City brass that has been sized, cleaned, and trimmed by the supplier. On the outside it looks beautiful, but the necks are tight and VERY “grabby”, perhaps due to their cleaning process. So, watch out for “etched” necks that are “too clean”. (There, that ought to set the hornets buzzing…)

By: Nate

Nate — Mon, 24 Apr 2017 00:43:04 +0000

Good lord, I’d look at neck tension before I started polishing stems.

Editor: Actually, we saw this with some 6mm bullets with relatively minimal neck tension. I quick spin with some polishing compound removed the sharp edge of the stem — problem solved. Another benefit was that the round-to-round bullet seating force seemed a little more consistent, though that is hard to quantify.